Fundamentals of Photography: How to Choose the Perfect Shutter Speed

This article, in the series of articles covering the fundamentals of photography, will take a closer look at shutter speed and how to use the right shutter speed to your advantage. As you’ll know from my previous article on the exposure triangle, shutter speed is one of the three main components affecting exposure.

What Is Shutter Speed?

Image taken with a short (fast) shutter speed to capture the water droplets of the waves

Every camera has a shutter, either physical or electronic (or both), which controls how much light can hit the sensor to capture an image. There are a range of different mechanisms for physical shutters (focal plane, leaf etc) but these act as physical barriers to light, opening for a specified time when you press the shutter button to take a photo, and then closing again. Electronic sensors work by turning the sensor on and off rather than physically blocking the light. Depending on the camera there will be a range of different mechanisms used for the shutter, but they have the same overall effect. It is only in a few certain situations, such as extremely fast shutter speeds or when synchronising with flash, where the specific type of shutter will really make a difference.

Shutter speed is therefore the length of time that the shutter stays open, controlling how much light hits the sensor or film. You might also see or hear shutter speed being called the exposure time, as it controls the length of time that the sensor is exposed to light.

Understanding how shutter speed can impact the overall exposure of your image, along with aperture and ISO (please see separate article on exposure triangle here) is essential for any photographer. Similarly, it is also essential to understand how shutter speed affects motion in your photos.

Shutter Speed and Exposure

Shutter speed has a very straightforward relationship with the exposure - how bright or dark your image is. The longer the shutter is open, the more light is able to enter the camera and hit the sensor or film, giving you a brighter image. Similarly, with a shorter exposure time, less light can enter the camera and hit the sensor giving you a darker image. Shutter speed needs to be balanced with the other parts of the exposure triangle (aperture and ISO) in order to produce an image with the optimal exposure.

There are a huge range of shutter speeds to use in photography, and selecting the best shutter speed based on your conditions and subject is essential to avoid over- or underexposing your image. Shutter speed is measured in time as fractions of a second (or seconds). A shutter speed of 1s means the shutter stays open for one second, whereas a shutter speed of 1/1000s means the shutter is open for one thousandth of a second. Generally, modern cameras have a range of shutter speeds from around as little as 1/8000s up to 30 seconds. You can also take photos using Bulb mode, which means the shutter stays open as long as the shutter release button is held.

Shutter Speed and Stops

By doubling your shutter speed, such as from 1/500s to 1/250s, you increase overall exposure by one stop and make the image brighter. Similarly, by halving shutter speed, from 1/500s to 1/1000s, you reduce the overall exposure by one stop and make the image darker. Most modern cameras allow you change the shutter speed in increments of one-third of a stop, such as 1/10, 1/13, 1/15 and 1/20, to give you more control.

Short (Fast) Shutter Speeds

Short (fast) shutter speed to freeze movement of bird’s wings.

Short shutter speeds allow you to freeze motion in your photos.

In the first instance, this can be essential in making sure that you don’t get blurry photos due to camera shake when hand-holding your camera. The steadiest hands in the world cannot stay perfectly still, so there will always be an element of camera shake when holding your camera. Using shorter shutter speeds allow you to prevent camera shake giving you blurry photos. The focal length of your lens (ie how zoomed in you are) has an impact on camera shake too. The higher the focal length and more zoomed in you are, the more camera shake will be visible as even tiny movements cause a big shift in where the camera is pointing.

As a general rule of thumb, you can make sure to use a shutter speed shorter (faster) than the focal length of your lens. For example, if using a 50mm lens, you can use a shutter speed of 1/50 or less to prevent blurry images from camera shake. Similarly, using a 200mm lens you can use a shutter speed of 1/200 or less.

To avoid camera shake altogether you can use a tripod so the camera is not moving, but this is not always possible. Many modern cameras and lenses also use technology called image stabilisation (IS), or in-built image stabilisation (IBIS), to reduce the impact of camera shake. IS technology is within the camera lens, and IBIS is within the camera itself. IS and IBIS is also measured in stops (the same as exposure). For example, with 2 stop image stabilisation, you can use a shutter speed two stops longer (such as 1/50 from 1/200) and the image should still be sharp. However, IS/IBIS have their own limitations, but that’s beyond the scope of this article.

Short shutter speeds also mean you can freeze motion in the subject of your photos. For example, when taking photos of moving subjects (moving cars, wildlife, sports) a short shutter speed will freeze the motion of your subject and give you a sharp image. Short shutter speeds can therefore give you pin-sharp images of water droplets in a crashing wave or the feathers of a bird’s flapping wings.

Long (Slow) Shutter Speeds

Image taken with shutter speed of 1/4s to smooth the falling water.

Longer shutter speeds can help you take well-exposed photos in very dark conditions, such as night-time or astrophotography. Often you need exposures of at least 10-30 seconds for astrophotography, when you’re trying to soak up as much as light as possible from distant stars.

Longer shutter speeds also help to capture a sense of movement in photos with moving subjects, which can allow you to be really creative.

For example, you can use a longer exposure time (such as 1/3s) when photographing moving water or clouds to give a smooth, silky effect, or to get trails of light from headlights/tail lights of moving cars. You’ll need to play around with shutter speed to really see the impact of this for yourself and get to grips with what shutter speed gives what effect. The best way to do this is to find a composition and set up your camera with a tripod, then use different shutter speeds to see what effect this has.

How Do I Choose Shutter Speed?

The choice of shutter speed all depends on what your subject is and what effect do you want. Do you want a super sharp image of a bird in flight? Choose a short (fast) shutter speed or around 1/1000s or shorter. Or do you want to smooth out waves crashing on the beach? Choose a longer (slower) shutter speed of around 1/4s or longer. There is only so much you can achieve with just a camera in terms of longer exposures, and you will reach a point where you need other gear (tripod, ND filters) to get the desired outcome. A full guide on long exposure photography will be covered in a separate article. Certainly the most essential piece of kit when you start thinking about shutter speeds of 1/4s or longer is a tripod, as this eliminates camera shake and means the only movement in your photos is of your subject.

It can be really valuable to use the shutter priority mode on your camera when first getting to grips with shutter speed, or when in conditions with rapidly changing light. Be sure to select a shutter speed appropriate for your subject and outcome, in other words is your subject moving and do you want to include a sense of movement in your photo. The camera can then adjust other settings as necessary to get a good exposure with that shutter speed. This gives you the flexibility to test the effects of different length shutter speeds without having to worry about all the other parts of exposure. So as a challenge, go out and take photos of different subjects at different shutter speeds. For example, find a waterfall and test different shutter speeds, such as 1/500s, 1/125s, 1/4s, 0.5s and 1s just to see how each photo looks different. With moving subjects such as people or wildlife, try different shutter speeds to get familiar with how each photo captures motion or not. Also be sure to take note of what other settings (aperture and ISO) you need to use to get the desired exposure, whether using auto, shutter-priority or manual modes. This will start to solidify your understanding of how shutter speed affects your photos and how shutter speed relates to the other elements of exposure triangle, as well as what your own individual camera is capable of.

I hope this has been a useful explanation of what shutter speed is and how it affects your photos, but the best way to really understand it is to go out there and play around with it! Happy photographing!